You can do this by adding an event handler to the frame change event.
import bpy def my_handler(scene): fm = bpy.data.scenes['Scene'].frame_current if fm >= 1: lampStrength = 100 if fm >= 50: lampStrength = 200 if fm >= 100: lampStrength = 300 if fm >= 150: lampStrength = 400 scene.objects['Point'].data.node_tree.nodes['Emission'].inputs['Strength'].default_value=lampStrength print("lamp strength: " + str(lampStrength)) def register(): bpy.app.handlers.frame_change_post.append(my_handler) def unregister(): bpy.app.handlers.frame_change_post.remove(my_handler) if __name__ == "__main__": register() Credit for frame change portion of script here: Running a script for each frame
